The Research And Improvement Of Topology Discovery Algorithm In Multi-VLAN Ethernet

Network topology is the study of the arrangement of links and nodes in a network and the interconnections among the nodes. We can categorize it as a physical network topology, where peers are connected to ports on devices via a transmission link or a logical network topology, in which a network is divided into logical segments through subnets (multi-VLAN Ethernet).Network discovery can also be categorized as Internet or backbone discovery and the local area network (LAN) or an organizational-level network such as autonomous system (AS) discovery. This article is only for local Ethernet (LAN) topology discovery algorithm research and improvement.Network topology information helps one analyze faults in networks and their locations. Rectifying such faults is a key role of network management system. Using the automatic discovery of network topology can help network operators find out the faults easily. Thus, the automatic discovery of network topology plays an important role in real work. For examples, an inexperienced network administrator joining an organization faces many difficulties due to the unavailability of a discovery tool, which otherwise would show the topology classification (based on types of devices and subnets) and layout of the networks. Even for the experienced administrator, keeping track of devices and their connectivity details, without having a proper method of visually presenting them becomes a difficult task.So, many studies conducted in the area of automatic discovery of network topology using ping, trace route, Simple Network Management Protocol (SNMP), and other methods have shown remarkable results. My algorithm research inherits their work and proposes a kind of algorithm based on SNMP. Moreover, I also have two improvements on that algorithm and apply the algorithm on my work for real-time testing. Using my algorithm, you can discover devices, including layer 2(L2 switches), layer 3 (L3 routers). Through practical work, tests prove that this topology discovery algorithm is feasible and using the algorithm could relieve the network management working strength, to a certain degree.